The header is the part of the agricultural harvester that comprises a harvester device which harvests a crop from the field on which said crop has grown. The harvester device in the header can for example be adapted to cut off grain plants, oils seed plants or corn, or it can for example be adapted to remove corn ears from corn stalks. The thus harvested crop is then transported by a header conveyor through the header to a header discharge. The header discharge is generally arranged centrally in the rear part of the header. For the transport of the crop through the header, a header auger is a common solution.
From the header discharge, the harvested crop enters the feeder house. The feeder house transports the harvested crop into the body of the agricultural harvester, where the crop can be processed, e.g. threshed. The feeder house can be pivotable relative to the body of the agricultural harvester.
It can be desirable that the header is pivotable relative to the feeder house. The header may be pivotable about a generally horizontal axis that extends substantially perpendicular to the longitudinal direction of the header, in order to follow the slope of the terrain. Instead or in addition, the header may also be pivotable about a generally horizontal axis that extends substantially parallel to the longitudinal direction of the header. This allows to obtain a desired cutting angle or pick up angle, even when it is desired to keep the same height for the front end of the feeder house. The cutting angle or pick up angle may for example have to be adjusted when switching to a different kind of crop, a crop with different properties or when the overall height of the body of the agricultural harvester is changed, e.g. due to the exchange of tires or a change in the tire pressure.
In order to allow movement and/or adjustment of the header and the feeder house relative to each other, a header adapter is provided between the feeder house and the header.
The header adapter in known agricultural harvesters is actuated by one or more actuators, which usually take the form of hydraulic cylinders.
In a known configuration, the header adapter is fixed to the header and pivotable relative to the feeder house via an adapter pivot that allows the header to pivot about a generally horizontal pivot axis that extends in a direction substantially parallel to the longitudinal direction of the header. The adapter pivot is usually arranged at or near the top of the feeder house adjacent to the header, at or near the bottom of the feeder house adjacent to the header or about halfway the top and the bottom of the feeder house adjacent to the header.
At least one hydraulic cylinder is in this known configuration arranged adjacent to the header on the feeder house for pivoting the header relative to the feeder house about a horizontal pivot axis which extends substantially parallel to the longitudinal axis of the header. Each cylinder that is used for pivoting the header relative to the feeder house about a horizontal pivot axis which extends substantially parallel to the longitudinal axis of the header is on one end attached to the feeder house and on the other end to the header adapter.
Additionally in such an arrangement, at least one cylinder is provided to pivot the feeder house relative to the body of the agricultural harvester. Each cylinder that is used for pivoting the feeder house relative to the harvester body is on one end attached to the harvester body and on the other end to the feeder house.
In these known arrangements, the adapter pivot has to be strong, because it supports the full weight of the header. Also, the cylinder or cylinders that are used to pivot the header relative to the feeder house have to be quite strong, or otherwise multiple cylinders have to be used, which increases the costs. Because the header is arranged in front of the adapter pivot and the header is heavy, the weight of the header causes a tilting moment that needs to be counteracted by the cylinder of cylinders in order to keep the header in the correct position. This requires one or more strong cylinders.
U.S. Pat. No. 8,826,635 describes an agricultural harvester that comprises a header adapter which is fixed to the header and pivotable relative to the feeder house through an adapter pivot. The adapter pivot is located about halfway the top and the bottom of the feeder house adjacent to the header. A first cylinder is provided, which on one end is connected to the feeder house and on the other end to the header adapter. In addition a second cylinder is provided. This cylinder is on one end connected to the harvester body and on the other end to the header adapter.
The second cylinder is used to pivot the feeder house and the header together relative to the harvester body. Due to this, all force required for lifting the heavy header and feeder house has to be borne by the adapter pivot. So, also in this known arrangement, the adapter pivot has to be strong. This makes the header adapter heavy.